Refrigeration



.s, 1936. A. R. "n-ioMA's REFRIGERATION '5 Sheets-Sheet 1 Filed NOV. 17,1934 lNV 'NTOR fin/44*; I .4; ATTORNEY A. R. THOMAS REFRIGERATION Dec.8, 1936.

Filed Noy. 17, 1934 3 Sheets-Sheet '2 INVENTOR MJF- WWW 5 ATTORNEY Dec.8, 1936. I A. R. THOMAS.

REFRIGERATION 5 Sheets-Sheet 3 Filed NOV. 17, 1934 lNVENT R fA BY'vATToRNEY 7 Patented Dec. 8, 1936 UNITED STATES PATENT OFFICEREFRIGERATION Albert R. Thomas, Evansville, Ind., assignor, by mesneassignments, to Servel, Inc., Dover, Del., a corporation oi. DelawareApplication November 1'1, 1934, Serial No. 753,415

4 Claims.

foregoing type in which the bulk of absorptionliquid is maintained incold condition during ex- 10 pulsion periods. I have found that if gasremoved from the evaporator is introduced into cold solution it isabsorbed too quickly particularly at the initial absorbing pressure,which is relatively high, to provide circulation due to therl5 mosiphonaction and a circulation of fresh ab- 7 withdrawn from the evaporatorinto residual hot 20 liquor left over from the previous expulsionperiod.

Other objects and the nature and advantages of my invention will beapparent from the following description considered in conjunction with25 the accompanying drawings forming a part of this specification, andof which:

Fig. 1 is a front view of a system embodying the invention;

Fig. 2 is a side view of the structure shown in 30 Fig. 1; and

Fig. 3 is a diagram of the apparatus shown in Figs. 1 and 2.

. The system includes an absorption liquid storage reservoir lll. Aconduit II is connected to 35 the upper part of reservoir l and isconnected to an analyzer vessel l2. A conduit i3 is connected to one endof analyzer I2 and extends downwardly and then upwardly to connect witha. thermosiphon conduit l4 which is connected to 40 a gas and liquidseparation vessel l5. Thermosiphon pipe I4 is equipped with flanges l6and is positioned above a heater l1 which may be a gas burner, anelectric heating element, a kerosene burner, or other source of heat.The burner and 45 thermosiphon conduit are surrounded by a hood l8having an ofitake I9. A conduit 20 is connected to vessel l and extendsthrough analyzer vessel l2 and through conduit II and opens into thelower part of vessel I 0.

50 A vapor conduit 2| is connected with the upper part of separatingvessel l5 and with the analyzer vessel l2. A conduit 22 opens intoanalyzer vessel 12 and communicates at the top with a conduit 23 whichextends upwardly to a vessel 24 and opens 55 therein. A conduit 25surrounds conduit 23, communicates at the top with vessel 24 andcommunicates at the bottom with a vessel 26. Vessel 25 is closed fromconduit 22 and conduit 23 except as communication is afforded throughconduit 25. A conduit 21 is connected to the upper part of 5 chamber orvessel 26 and in part passes through fins 28 to form a condenser 29.Conduit 21 continues beyond the condenser to connect with the upper partof an evaporator 30. A drain conduit 3| is connected to the lower partof evaporator 30 and extends upwardly as shown and is in part in heatexchange relation with conduit 25. A conduit 32 connects chamber 26 witha point 33 in a conduit 34. Conduit 34 extends from the lower part ofvessel I5 downwardly and then upwardly to connect with a volumevariation vessel 35. Ahsorber fins 36 are provided on conduit 34 to forman absorber 31. Within the volume variation vessel is a partition 38having an aperture 39 therein and forming chambers 40 and 4|. Cham her40 is connected by a pipe 42 with conduit H.

Chamber 4| is connected by means of a conduit 43 with reservoir I0. 44represents insulation surrounding the volume variation vessel 35, theseparating vessel I5, analyzer l2, and the major portion of conduits IIand 20. Conduits II and 20 form a liquid heat exchanger 45. A thermostatbulb 46 in heat exchange with vessel l5 and a thermostat bulb 41 is inheat exchange with the evaporator 30. The evaporator is so arranged 30as to take up heat from the body to be cooled.

A conduit 48 is connected between chamber 2 and volume variation vessel35.

The system contains a solution of ammonia or other suitable refrigerantin an absorption liquidsuch as water or other suitable liquid. In theactual apparatus shown in Figs. 1 and 2, the height H is equal to 22%inches from which the other dimensions can be determined. This apparatuswas charged with 6 liters of ammonia solution of a concentration of 32per cent.

. I have operated the systemshown in Figs. 1 and 2 with a control suchas shown in application Serial No. 728,670 filed June 2, 1934 by S. W.E. Andersson.

In operation, heat is applied by means of the heater l1 and vapor isexpelled from solution in the thermosiphon conduit I4. The vapor andliquid pass into the separation vessel I 5. The gas expelled fromsolution passes through conduit 50 2| and into analyzer vessel I2. Ihave indicated the flow of ammonia vapor by arrows without tails. Fromvessel l2, the vapor passes through conduits 22 and 23 into vessel 24.Thence the ammonia vapor passes downwardly through conduit 25 bubblingthrough liquid in chamber 26 and through conduit 21 into the condenser29. In the condenser the vapor is liquefied and the condensate passesthrough conduit 21 into the evaporator 30 where it accumulates. I haveindicated the flow of condensed ammonia by arrows with a V tail.

The expulsion of vapor in conduit l4 also sets up a circulation ofliquid between the member l4 and the absorption liquid reservoir Iindicated by arrows with round tails as follows:

The liquid passes into the separating vessel l and thence throughconduit 20into reservoir I0.

Liquid passesirom the reservoir l0 through conduit II and throughanalyzer l2 and into conduit l3 and to member I4. This circulation ismaintained due to the generation of vapor in member M. The gas flowingthrough conduit 2| and analyzer l2 passes over the surface of liquidflowing to member l4. This serves to preheat the liquid passing to theheating member I4 and to cool and remove water vapor from the gaspassing toward the condenser. The cold solution passing through conduitII is heated by the warm solution flowing in conduit 20 and thereforethe absorption liquid entering the reservoir in is cooled. The reservoirII) is preferably exposed to atmospheric cooling. As the expulsionperiod proceeds the liquid level or surface level in chamber 40 movesdownwardly, this chamber supplying theliquid differential to take careof the gas driven OE and accumulated in the evaporator 30.

When a suflicient amount of ammonia is driven out of solution, which isrepresented by a rise in temperature of'bulb 46, the supply of heat isshut off and the low pressure evaporation or expulsion period thenstarts. Cooling of the hot section of the system causes condensation andsome absorption takes place as a result of which the pressure in the gasspace above the residual hot liquid is reduced relative to the pressurein the evaporator. This causes liquid to be drawn up in tube 25 and aliquid column is thus formed. which provides a pressure differential forforcing gas from the evaporator into the absorption liquid. The gasflows from the evaporator through conduit 21 in the opposite directionto that previously described and is indicated by arrows with squaretails. It flows through vessel 26 and into conduit 32, enteringabsorption liquid in pipe 34 at 33. This causes a flow of liquid inducedby gas lift action which is indicated by arrows with S-shaped tails.This flow takes place upwardly in conduit 34 to absorber 31, thencethrough chamber 4| and downwardly through. conduit 43 and into reservoirIII. In the absorber 3'! the gas is absorbed by the liquid. From thereservoir I0, the liquid passes through conduit 20 and vessel 15 back toconduit 34. During the absorption periods," the liquid level stands at ahigher level in vessels I5 and e 22. Conduit 48 provides equalization ofpressure tion periods. Some of the liquid circulated during absorptionperiods flows through aperture 39 and the amount of liquid in chamber 40increases as the absorption period progresses. It will be seen that thegas coming from the evaporator is introduced into liquid withdrawn fromchamber l5 which contains residual hot liquid from the previousexpulsion period. Due to the introduction of the gas into hot liquid,the gas is not so quickly dissolved and an appreciable column of gas andliquid is formed in one vertical leg of the absorption liquidcirculation system thus facilitating this circulation.

I prefer to construct the boiler of the system in the form of a finnedtube (thermosiphon conduit l4) I have found that this structure combineseflicient heating and light weight. Preferably the tube is inclined fromthe horizontal at an angle less than 45, for instance, about 20.

It will be obvious that the invention can be applied to a variety ofstructures.

I claim:

1. In an absorption refrigeration system having low pressure periods ofrefrigerant evaporation and absorption alternating with higher pressureperiods of vapor expulsion and condensation, a hot liquid section, acold liquid section, conduits forming a first path of flow for liquidfrom the hot liquid section to the cold liquid section and a second pathof flow from the cold liquid section to the hot liquid section, anevaporator, and means to conduct gas from the evaporator and introduceit into said first path;

2. In an absorption refrigeration system having low pressure periods ofrefrigerant evaporation alternating with higher pressure periods ofvapor expulsion and condensation, an absorption liquid reservoir adaptedto hold the bulk of absorption liquid in relatively cold state duringexpulsion periods, a hot liquid section. a conduit connecting said hotliquid section with said reservoir, an evaporator, and means to conductvapor from the evaporator and introduce it into said conduit to causeflow of liquid from the hot liquid section to the reservoir.

3. In an absorption refrigeration system having low pressure periods ofrefrigerant evaporation alternating with higher pressure periods ofvapor expulsion and condensation, a gas and liquid separation vessel,means to s ply gas and liquid thereto during expulsion periods, anabsorption liquid reservoir, a conduit connecting said separation vesselwith said reservoir, an evaporator, and means to conduct gas from saidevaporator and introduce it into said conduit.

4. In an absorption refrigeration system having low pressure periods ofrefrigerant evaporation alternating with higher pressure periods ofvapor expulsion, the improvement which consists period into hot residualliquor remaining from the previous expulsion period to cause circulationof liquid.

ALBERT R. THOMAS.

